KR20190100336A - Method for producing vinyl polymer - Google Patents

Abstract

As a manufacturing method of the vinyl polymer which suspend-polymerizes a vinyl compound in presence of the dispersion stabilizer for suspension polymerization; The dispersion stabilizer contains a modified polyvinyl alcohol (A) and a composition (C) containing a compound (B) and a polyvinyl alcohol (E), and the modified polyvinyl alcohol (A) is derived from an unsaturated carboxylic acid or a derivative thereof. The compound which has a double bond to a side chain, and compound (B) has two or more hydroxyl groups couple | bonded with the conjugated double bond, The modified polyvinyl alcohol (A) and polyvinyl alcohol (E) have a degree of saponification and a viscosity average polymerization degree The content of the compound (B) in the composition (C) is 0.001 part by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the modified polyvinyl alcohol (A), and the composition (C) and polyvinyl alcohol (E Disclosed is a production method in which the mass ratio (C / E) to) is 50/50 to 90/10. Thereby, when carrying out suspension polymerization of a vinyl compound, while showing high polymerization stability, coloring and fisheye of the polymer obtained can be suppressed.

Description

Method for producing vinyl polymer

TECHNICAL FIELD This invention relates to the manufacturing method of the vinyl polymer which suspend-polymerizes a vinyl compound in presence of the dispersion stabilizer for polymerization containing polyvinyl alcohol.

Polyvinyl alcohol (hereinafter sometimes abbreviated as "PVA") is conventionally a suspension polymerization of an adhesive, a paper coating agent, a polarizing film, a water-soluble film, a medicine, a composition for cosmetics, and a vinyl compound (for example, vinyl chloride). It is used for various products, such as dispersion dispersion stabilizer. In many products, the coloring of PVA is small and white, and the added value of a product becomes high. It is also known that various performances can be improved or special effects can be obtained by the presence of reactive groups such as double bonds in PVA.

 PVA is widely used as a dispersion stabilizer used for suspension polymerization of a vinyl compound (patent documents 1-5).

In order to improve the stability (polymerization stability) at the time of superposition | polymerization of vinyl chloride, using heat-treated PVA for a polymerization reaction is proposed (patent documents 1-3). However, when suspension polymerization of vinyl chloride was carried out using these PVAs as a dispersion stabilizer, a satisfactory effect was not obtained in terms of polymerization stability. In addition, these conventional PVAs are very poor in color, and therefore, the color of the vinyl polymer obtained is also poor.

Patent document 4 describes the dispersion stabilizer for suspension polymerization which contains the polyvinyl alcohol which has a double bond in the side chain obtained by acetalizing polyvinyl alcohol by the monoaldehyde which has an olefinic unsaturated double bond. . When the polymerization reaction was carried out using the dispersion stabilizer for suspension polymerization described in Patent Literature 4, although a certain effect was observed for color improvement, it was difficult to say that the polymerization stability and the plasticizer absorbency of the vinyl polymer obtained were sufficient.

Moreover, since acid was used when manufacturing the polyvinyl alcohol of patent document 4, there also existed a problem that the expensive installation which is resistant to acid was needed. In addition, monoaldehydes having a double bond, which are used in the production of the polyvinyl alcohol, are expensive, unstable in air, designated as poisons, have poor handling properties due to irritating odor, and lack of raw material supplyability. There was a problem such as.

Patent Document 5 describes a dispersion stabilizer made of polyvinyl alcohol having a double bond in a side chain, obtained by esterifying polyvinyl alcohol with a carboxylic acid having a unsaturated double bond or a salt thereof. Polyvinyl alcohol used for this dispersion stabilizer is said to be obtained by a simple method using inexpensive carboxylic acid.

However, the polyvinyl alcohol in which the double bond is introduced into the side chain obtained by the conventional method is insufficient in color improvement, and the color of the vinyl polymer obtained when the vinyl compound is polymerized using a dispersion stabilizer made of this polyvinyl alcohol. The improvement is also insufficient. Moreover, since the dispersion stabilizer of patent document 5 contains the insoluble thing about water, when the suspension polymerization of a vinyl compound is carried out using this dispersion stabilizer, the fish eye arises in the vinyl polymer obtained, too. there was.

Patent Document 1: Japanese Patent Application Laid-Open No. 51-45189 Patent Document 2: Japanese Patent Application Laid-Open No. 10-67806 Patent Document 3: Japanese Patent Application Laid-Open No. 2004-250695 Patent Document 4: International Publication 2015/182567 Patent Document 5: International Publication No. 2007/119735

This invention is made | formed in order to solve the said subject, and when providing suspension polymerization of a vinyl compound, it aims at providing the manufacturing method of the vinyl polymer which can exhibit high polymerization stability and can suppress coloring and fisheye of the polymer obtained. It is to be done.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, the present inventor completes the composition (C) containing the modified polyvinyl alcohol (A) which has a specific amount in a side chain the double bond derived from an unsaturated carboxylic acid or its derivative (s), and a specific compound (B). I was. And when using the dispersion stabilizer for suspension polymerization containing this composition (C) and polyvinyl alcohol (E), it discovered that suspension polymerization reaction of a vinyl compound is stabilized. Moreover, coloring and fisheye of the vinyl polymer obtained were also suppressed.

That is, the said subject is a manufacturing method of the vinyl polymer which suspend-polymerizes a vinyl compound in presence of the dispersion stabilizer for suspension polymerization; The dispersion stabilizer contains a modified polyvinyl alcohol (A) and a composition (C) containing a compound (B) and a polyvinyl alcohol (E), and the modified polyvinyl alcohol (A) is derived from an unsaturated carboxylic acid or a derivative thereof. The double bond which has a double bond to a side chain is 0.01 mol% or more and less than 2 mol%, The saponification degree of modified polyvinyl alcohol (A) is 65 mol% or more and less than 77 mol%, Viscosity average degree of polymerization is 400 or more and less than 1500, Compound (B) (A) A compound having two or more hydroxyl groups bonded to a conjugated double bond, or a salt thereof or an oxide thereof, wherein the saponification degree of polyvinyl alcohol (E) is 77 mol% or more and less than 97 mol%, and the viscosity average degree of polymerization is 1500 or more and 5000 It is less than 0.001 mass part or more and less than 5 mass parts with respect to 100 mass parts of modified polyvinyl alcohol (A), and content of a compound (B) in a composition (C) is a composition (C) and polyvinyl alcohol (E) The mass ratio (C / E) between and 50/50 to 90/10 It is solved by providing a process for producing the same.

At this time, it is preferable that compound (B) is a compound in which two or more hydroxyl groups couple | bonded with the carbon which comprises an aromatic ring, its salt, or its oxide. It is also preferred that the composition (C) is a powder and that the yellow index of the powder is less than 50.

According to the production method of the present invention, the polymerization reaction is stable, and formation of coarse and large particles is reduced. Moreover, coloring and fisheye of the polymer obtained can also be suppressed.

(Composition (C))

The composition (C) used in the present invention includes a modified polyvinyl alcohol (A) (hereinafter sometimes abbreviated as "modified PVA (A)") and a compound having a double bond derived from an unsaturated carboxylic acid or a derivative thereof in the side chain. (B) is characterized by including a specific amount. Although the manufacturing method of the composition (C) used by this invention is not specifically limited, A suitable manufacturing method is a method of making polyvinyl alcohol (D), unsaturated carboxylic acid, or its derivative (s) react in presence of a compound (B). Here, polyvinyl alcohol (D) is PVA which does not have a double bond in a side chain (it may describe as "PVA (D)" or "raw material PVA" hereafter).

(Modified PVA (A))

The raw material PVA (PVA (D)) can be produced by polymerizing a vinyl ester monomer by employing a conventionally known method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method or a dispersion polymerization method. have. Preferred polymerization methods from the industrial standpoint are solution polymerization method, emulsion polymerization method and dispersion polymerization method. In the case of a polymerization operation, it is also possible to employ | adopt either polymerization method of a batch method, a semibatch method, and a continuous method.

As a vinyl ester type monomer which can be used for superposition | polymerization, vinyl acetate, a vinyl formate, a vinyl propionate, a vinyl caprylate, a vinyl versatate, etc. are mentioned, for example, vinyl acetate is preferable from an industrial viewpoint.

As long as it is a range which does not impair the meaning of this invention at the time of superposition | polymerization of a vinyl ester type monomer, you may copolymerize a vinyl ester type monomer with another monomer. As another monomer which can be used, For example, alpha-olefins, such as ethylene, propylene, n-butene, isobutylene; Acrylic acid and its salt, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, etc. Acrylic acid esters; Methacrylic acid and its salts; Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-methacrylate Methacrylic acid esters such as ethylhexyl, dodecyl methacrylate and octadecyl methacrylate; Acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetone acrylamide, acrylamide propanesulfonic acid and its salts, acrylamidepropyldimethylamine and its salts or quaternary salts thereof, N Acrylamide derivatives such as methylol acrylamide and derivatives thereof; Methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propanesulfonic acid and its salts, methacrylamide propyldimethylamine and its salts or quaternary salts thereof, N-methylol methacrylamide and its Methacrylamide derivatives such as derivatives; Vinyl such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether Ethers; Nitriles such as acrylonitrile and methacrylonitrile; Vinyl halides such as vinyl chloride and vinyl fluoride; Vinylidene halides such as vinylidene chloride and vinylidene fluoride; Allyl compounds such as allyl acetate and allyl chloride; Unsaturated dicarboxylic acids and salts thereof or esters thereof such as maleic acid, itaconic acid and fumaric acid; Vinylsilyl compounds such as vinyltrimethoxysilane; Isopropenyl acetate etc. are mentioned. The copolymerization amount of such another monomer is 10 mol% or less normally.

In addition, a chain transfer agent may coexist for the purpose of adjusting the polymerization degree of the polyvinyl ester obtained at the time of superposition | polymerization of a vinyl ester monomer, and the like. Examples of the chain transfer agent include aldehydes such as acetaldehyde, propionaldehyde, butyl aldehyde and benzaldehyde; Ketones such as acetone, methyl ethyl ketone, hexanone and cyclohexanone; Mercaptans such as 2-hydroxyethane thiol and dodecyl mercaptan; Halogenated hydrocarbons, such as trichloroethylene and perchloroethylene, are mentioned, Especially, aldehydes and ketones are used suitably. Although the addition amount of a chain transfer agent is determined according to the chain transfer constant of the chain transfer agent to add, and the degree of polymerization of the polyvinyl ester desired, 0.1-10 mass% is generally preferable with respect to polyvinyl ester.

The saponification reaction of polyvinyl ester can be applied to an alcoholic decomposition or hydrolysis reaction using a conventionally known basic catalyst such as sodium hydroxide, potassium hydroxide, sodium methoxide, or an acidic catalyst such as p-toluenesulfonic acid. As a solvent used for saponification reaction, Alcohol, such as methanol and ethanol; Esters such as methyl acetate and ethyl acetate; Ketones such as acetone and methyl ethyl ketone; Aromatic hydrocarbons, such as benzene and toluene, etc. are mentioned, These can be used individually or in combination of 2 or more types. Especially, it is simple and preferable to perform saponification reaction in presence of sodium hydroxide which is a basic catalyst using methanol or the mixed solution of methanol and methyl acetate as a solvent.

Examples of the unsaturated carboxylic acid or derivative thereof used in the present invention include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, propinic acid, 2-pentenoic acid, 4-pentenoic acid, 2-heptenic acid, 2-octenic acid, cinnamic acid, Myristoleic acid, palmitoleic acid, oleic acid, elideic acid, barksenic acid, gadoleic acid, erucic acid, nerbonic acid, linoleic acid, linolenic acid, eleostearic acid, stearic acid, arachidonic acid, eicosapentaenoic acid, gluconate Unsaturated monocarboxylic acids such as panodonic acid, docosahexaenoic acid and sorbic acid; Unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid and mesaconic acid; Unsaturated carboxylic anhydrides such as maleic anhydride, itaconic anhydride and citraconic anhydride; Unsaturated carboxylic acid alkyl esters such as acrylic acid alkyl esters, methacrylic acid alkyl esters and crotonic acid alkyl esters; Unsaturated dicarboxylic acid monoesters such as maleic acid monoalkyl esters, such as maleic acid monomethyl ester (mono maleic acid), fumaric acid monoalkyl esters, and itaconic acid monoalkyl esters; Unsaturated dicarboxylic acid diesters, such as a maleic acid dialkyl ester, a fumaric acid dialkyl ester, and itaconic acid dialkyl ester, are mentioned. These carboxylic acids can also be used as a salt. Carboxylic acid or its salt can be used individually or in combination of 2 or more types.

Among these, it is preferable that the unsaturated carboxylic acid or its derivative used by this invention is an unsaturated dicarboxylic acid, an unsaturated carboxylic anhydride, or an unsaturated dicarboxylic acid monoester from a viewpoint of the reactivity with the hydroxyl group of raw material PVA. From the viewpoint that the boiling point is somewhat high and easy to handle, the unsaturated carboxylic acid or derivatives thereof is more preferably maleic anhydride, citraconic acid, itaconic acid or maleic acid monoalkyl ester, and from the viewpoint of reactivity, maleic anhydride and itaconic acid It is more preferable that it is a maleic acid monoalkyl ester, and it is especially preferable that it is itaconic acid.

It is important that the modified PVA (A) has 0.01 mol% or more and less than 2 mol% in the side chain of a double bond derived from an unsaturated carboxylic acid or a derivative thereof. Here, the modified PVA (A) having a double bond derived from an unsaturated carboxylic acid or a derivative thereof in a side chain of 0.01 mol% or more and less than 2 mol% is a double bond derived from a unsaturated PVA (A) derived from an unsaturated carboxylic acid or a derivative thereof. It has in a side chain, and the said double bond amount means 0.01 mol% or more and less than 2 mol% with respect to all monomer units.

In the case of suspension polymerization of a vinyl compound using a dispersion stabilizer for suspension polymerization containing a modified PVA (A) having an amount of the double bond of less than 0.01 mol%, the polymerization stability is lowered to form many coarse and large particles, and the fish eye Problems, such as many polymers, are obtained. It is preferable that the quantity of the said double bond is 0.03 mol% or more.

On the other hand, the modified PVA (A) having an amount of the above double bond of 2 mol% or more is difficult to produce and has low productivity even if it can be produced. The composition (C) containing such modified PVA (A) is bad in color, and furthermore, insoluble matters are produced when dissolved in water. In addition, when the amount of the double bond is suspended and polymerized with a vinyl compound using a dispersion stabilizer for suspension polymerization containing 2 mol% or more of modified PVA (A), the color of the obtained polymer is bad and there are many fish eyes. It is preferable that the quantity of the said double bond is less than 1.7 mol%. In addition, the double bond means a carbon-carbon double bond.

The amount of the double bond derived from the unsaturated carboxylic acid or derivatives thereof of the modified PVA (A) can be measured by a known method. Specifically, the measurement by ¹ H-NMR is easy. When measuring the quantity of the double bond derived from the unsaturated carboxylic acid or its derivative of modified PVA (A), it is preferable to remove after unreacted unsaturated carboxylic acid or its derivative previously, and to refine | purify. There is no restriction | limiting in particular in a purification method, The method of wash | cleaning with the solution which a modified PVA (A) does not melt | dissolve and an unreacted unsaturated carboxylic acid or its derivative is melt | dissolved is mentioned, However, First, denaturation PVA (A) is carried out in concentration 1-20. After making it into the aqueous solution about the mass%, the reprecipitation method which refines | purifies by dropping an aqueous solution in the solution in which unmodified unsaturated carboxylic acid or its derivative is melt | dissolved, without melt | dissolving modified PVA (A), is precipitated. And preferred.

The degree of saponification of the modified PVA (A) is 65 mol% or more and less than 77 mol%. It is preferable that the saponification degree of modified PVA (A) is 67 mol% or more. On the other hand, it is preferable that saponification degree of modified PVA (A) is less than 75 mol%. Saponification degree is a value obtained by measuring according to JIS-K6726 (1994).

The viscosity average polymerization degree of modified PVA (A) is 400 or more and less than 1500. It is preferable that the viscosity average polymerization degree of modified PVA (A) is 500 or more. On the other hand, it is preferable that it is less than 1000, and, as for the viscosity average polymerization degree of modified PVA (A), it is more preferable that it is less than 900. In the case where the saponification degree is less than 99.5 mol%, with respect to PVA saponified until the saponification degree is 99.5 mol% or more, intrinsic viscosity [η] (liter / g) measured at 30 degreeC in water, Viscosity average polymerization degree (P) was calculated | required.

P = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

(Compound (B))

The compound (B) in this invention is a compound which has a conjugated double bond, and has two or more hydroxyl groups couple | bonded with the said conjugated double bond, its salt, or its oxide. Here, the hydroxyl group couple | bonded with the conjugated double bond means the hydroxyl group couple | bonded with the carbon which comprises the conjugated carbon-carbon double bond.

Examples of the compound having a conjugated double bond include conjugated polyenes having a structure in which carbon-carbon double bonds and carbon-carbon single bonds are alternately connected. As a conjugated polyene, a conjugated diene having a structure in which two carbon-carbon double bonds and one carbon-carbon single bond are alternately connected, and a structure in which three carbon-carbon double bonds and two carbon-carbon single bonds are alternately connected And conjugated triene to have.

The conjugated polyene also includes a conjugated polyene in which a conjugated double bond composed of a plurality of carbon-carbon double bonds does not conjugate with each other and has a plurality of sets in one molecule. The conjugated polyene may be linear or cyclic.

The compound having a conjugated double bond includes not only the above-described conjugated polyene but also an aromatic hydrocarbon such as benzene or an α, β-unsaturated carbonyl compound having a carbon-carbon double bond conjugated with a carbonyl group in a molecule.

In the compound (B), the hydroxyl group may be bonded to the carbon constituting the conjugated carbon-carbon double bond, and the bonding position is not particularly limited, and the total number of hydroxyl groups may be two or more. When the compound which has a conjugated double bond is a conjugated polyene, the compound which the hydroxyl group couple | bonded with unsaturated carbon is mentioned. When the compound which has a conjugated double bond is an aromatic hydrocarbon, the compound which the hydroxyl group couple | bonded with the carbon which comprises an aromatic ring is mentioned. When the compound which has a conjugated double bond is an (alpha), (beta)-unsaturated carbonyl compound, the compound which the hydroxyl group couple | bonded with the (alpha) position and (beta) position is mentioned.

Among these, as a compound (B), the compound in which two or more hydroxyl groups were couple | bonded with the carbon which comprises an aromatic ring from the viewpoint which can further suppress coloring and fisheye of the vinyl polymer obtained, its salt, or its oxide Is preferably.

 Examples of the compound in which two or more hydroxyl groups are bonded to the carbon constituting the aromatic ring include polyphenols. Examples of the polyphenols include hydroxybenzene. As hydroxybenzene, Benzene diol, such as hydroquinone, catechol, resorcinol; Benzenetriols such as pyrogallol, phloroglucinol and hydroxyquinol; Hexahydroxybenzene, etc. are mentioned. Moreover, as said polyphenol, Phenol carboxylic acids, such as gallic acid; Phenol carboxylic acid esters such as gallic acid alkyl esters; Catechins, such as epicatechin, epigallocatechin, and epigallocatechin-3-gallate, are also mentioned. Examples of the gallic acid alkyl ester include methyl gallate, ethyl gallate, propyl gallate, octyl gallate, and dodecyl gallate.

Among these, the compound (B) is preferably any one of hydroxybenzene, phenol carboxylic acid and phenol carboxylic acid ester, more preferably benzenediol, gallic acid and alkyl gallate, and still more preferably hydroquinone or alkyl gallate. In addition, the gallic acid alkyl ester is particularly preferable from the viewpoint of safety.

Moreover, ascorbic acid etc. are mentioned as a compound which the hydroxyl group couple | bonded with the (alpha) position and (beta) position of the (alpha), (beta)-unsaturated carbonyl compound.

The compound (B) used in the present invention may be a salt of the compound described above. The salt in this case means the thing of the metal alkoxide which the hydrogen of the hydroxyl group couple | bonded with the conjugated double bond was substituted by the metal, and the carboxylate whose hydrogen of the carboxyl group in a molecule was substituted by the metal. Examples of the metal include sodium and potassium. As a salt of the compound which has two or more hydroxyl groups couple | bonded with the conjugated double bond, For example, gallates, such as sodium gallate; Ascorbates, such as sodium ascorbate, are mentioned.

The compound (B) used in the present invention may be an oxide of the compound described above. The oxide in this case means that the hydroxyl group bonded to the conjugated double bond is oxidized. As such a compound, benzoquinone, dehydroascorbic acid, etc. are mentioned.

In the present invention, the compound (B) is a compound having a conjugated double bond and having two or more hydroxyl groups bonded to the conjugated double bond or a salt thereof in view of performance as a dispersion stabilizer for suspension polymerization of the composition (C). It is preferable that it is a compound which has two or more hydroxyl groups couple | bonded with the conjugated double bond.

(Method for Producing Composition (C))

The composition (C) in this invention contains a modified polyvinyl alcohol (A) and a compound (B). Although the manufacturing method of a composition (C) is not specifically limited, A suitable manufacturing method is a method of making PVA (D) (raw material PVA), unsaturated carboxylic acid, or its derivative (s) react in presence of a compound (B). At this time, in order to accelerate the reaction, heating is preferably performed when the reaction is performed. It is preferable that heating temperature is 80-180 degreeC. The heating time is appropriately set in relation to the heating temperature, but is usually 10 minutes to 24 hours.

As a method for reacting the raw material PVA with an unsaturated carboxylic acid or its derivative in the presence of the compound (B), a powder of the raw material PVA is added to the solution after obtaining a solution in which the unsaturated carboxylic acid or its derivative and the compound (B) are dissolved in a liquid. After adding and swelling, the method of obtaining a mixed powder by removing the said liquid and heating the obtained mixed powder is preferable. Thus, by reacting in solid in presence of a compound (B), undesirable crosslinking reaction can be suppressed and a composition (C) with favorable water solubility can be obtained. By this reaction method, the powder which consists of a composition (C) can be obtained. As a liquid which melt | dissolves a compound (B), alcohol, such as methanol, ethanol, a propanol, water, etc. are used. Removal of the liquid can be carried out by heating or reduced pressure, preferably by reduced pressure.

In the said reaction method, it is preferable that content of unsaturated carboxylic acid or its derivative in mixed powder before heating is 0.01 mass part or more with respect to 100 mass parts of raw materials PVA, It is more preferable that it is 0.1 mass part or more, 0.5 mass It is especially preferable that it is more than a part. On the other hand, it is preferable that content of unsaturated carboxylic acid or its derivative in the mixed powder before heating is 10 mass parts or less with respect to 100 mass parts of raw materials PVA, It is more preferable that it is 7 mass parts or less, It is more preferable that it is 5 mass parts or less. It is preferable and it is especially preferable that it is 3.5 mass parts or less. In the composition (C), the raw material PVA contained in the mixed powder before heating becomes a modified PVA (A), and the compound (B) remains as it is.

In this invention, it is important that content of the compound (B) in a composition (C) is 0.001 mass part or more and less than 5 mass parts with respect to 100 mass parts of modified PVA (A). When content of the compound (B) in a composition (C) is less than 0.001 mass part with respect to 100 mass parts of modified PVA (A), the hue of the composition (C) obtained deteriorates. In addition, dissolving the composition (C) in water produces insoluble matter. Moreover, when such a composition (C) is used as a dispersion stabilizer for suspension polymerization of a vinyl compound, the color of the polymer obtained is bad and there are many fish eyes. It is preferable that content of the compound (B) in a composition (C) is 0.005 mass part or more with respect to 100 mass parts of modified PVA (A), It is more preferable that it is 0.01 mass part or more, It is further more preferable that it is 0.05 mass part or more.

On the other hand, when content of the compound (B) in a composition (C) is 5 mass parts or more with respect to 100 mass parts of modified PVA (A), when a composition (C) is used as a dispersion stabilizer for suspension polymerization of a vinyl compound, it will be obtained. The average particle diameter of vinyl polymer particle | grains becomes large, or many coarse and large particle | grains are formed. In addition, the fish eye of the vinyl polymer obtained increases. It is preferable that content of the compound (B) in a composition (C) is 3 mass parts or less, It is more preferable that it is 2 mass parts or less, It is further more preferable that it is 1 mass part or less.

Although the form of a composition (C) is not specifically limited, From a viewpoint of the dissolution rate with respect to water, it is preferable that it is a powder. The particle diameter of the powder at this time is 50-2000 micrometers normally. The particle diameter of the powder is the average particle diameter determined by the method of JIS-K6726 (1994).

It is preferable that the yellowness (hereinafter, abbreviated as "YI") of the powder made of the composition (C) is less than 50. When YI is 50 or more, when the composition (C) is used as a dispersion stabilizer for suspension polymerization of a vinyl compound, there exists a possibility that the color of the vinyl polymer obtained may deteriorate. It is more preferable that it is 40 or less, and, as for YI, it is more preferable that it is 30 or less. YI in this specification is the value measured and calculated according to JIS-Z8722 (2009) and JIS-K7373 (2006).

[Polyvinyl Alcohol (E)]

In the present invention, the polyvinyl alcohol (E) (hereinafter abbreviated as PVA (E)) used with the composition (C) may be unmodified or may be modified, but the degree of saponification and viscosity average polymerization degree All are different from the modified PVA (A) included in the composition (C). The saponification degree of PVA (E) is 77 mol% or more and less than 97 mol%. It is preferable that it is 80 mol% or more, and, as for the saponification degree of PVA (E), it is more preferable that it is 82 mol% or more. On the other hand, it is preferable that it is less than 95 mol%, and, as for the saponification degree of PVA (E), it is more preferable that it is less than 92 mol%. Saponification degree is the value obtained by measuring according to JIS-K6726 (1994).

The viscosity average degree of polymerization of PVA (E) is 1500 or more and less than 5000. It is preferable that the viscosity average polymerization degree of PVA (E) is 1800 or more. On the other hand, it is preferable that the viscosity average polymerization degree of PVA (E) is less than 4000, It is more preferable that it is less than 3000, It is especially preferable that it is less than 2800. When the saponification degree is less than 99.5 mol%, the following formula is used by using the intrinsic viscosity [η] (liter / g) measured at 30 ° C in water with respect to saponified PVA until the saponification degree is 99.5 mol% or more. Viscosity average polymerization degree (P) was calculated | required.

P = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

(Method for producing vinyl polymer)

This invention is a manufacturing method of the vinyl polymer which suspend-polymerizes a vinyl compound in presence of the dispersion stabilizer for suspension polymerization containing a composition (C) and PVA (E). When such a dispersion stabilizer is used for suspension polymerization of a vinyl compound, the polymerization reaction is stabilized and the formation of coarse and large particles is reduced. Moreover, coloring and fisheye of the vinyl polymer obtained can be suppressed.

The mass ratio (C / E) of the composition (C) and PVA (E) in the dispersion stabilizer is 50/50 to 90/10. By making mass ratio (C / E) of a composition (C) and PVA (E) into the said range, superposition | polymerization of a vinyl compound becomes more stable and the particle diameter of the vinyl polymer particle obtained becomes more uniform. It is preferable that mass ratio (C / E) is 55/45-80/20.

The said dispersion stabilizer may contain various additives other than a composition (C) and PVA (E) in the range which does not impair the meaning of this invention. As said additive, For example, polymerization regulators, such as aldehydes, halogenated hydrocarbons, mercaptans; Polymerization inhibitors such as phenol compounds, sulfur compounds and N-oxide compounds; pH adjusters; Crosslinking agents; antiseptic; Preservatives; Antiblocking agents, antifoaming agents, compatibilizers and the like. It is preferable that it is 10 mass% or less with respect to the total amount of a composition (C) and PVA (E), and, as for content of various additives in the dispersion stabilizer for suspension polymerization, it is more preferable that it is 5 mass% or less.

The injection method of the said dispersion stabilizer into the polymerization tank is not specifically limited. As an injection method, (i) the method of mixing PVA (E) and composition (C) in powder form, and then inject | pouring into a polymerization tank as aqueous solution, (ii) the composition (C) and PVA (E) prepared as each aqueous solution. Then, the method of inject | pouring the aqueous solution obtained by mixing these into a polymerization tank, (iii) The method of preparing a composition (C) and PVA (E) as each aqueous solution, and then inject | pouring into each polymerization tank without mixing these in aqueous solution. and (iv) a method of injecting the composition (C) and PVA (E) in a powder state, and the like, but are not particularly limited. From the point of uniformity in the polymerization tank, the method of any one of the above methods (i), (ii) and (iii) is preferred.

As a vinyl compound used for the manufacturing method of the vinyl polymer of this invention, Vinyl halides, such as vinyl chloride; Vinyl esters such as vinyl acetate and vinyl propionate; Acrylic acid, methacrylic acid, esters and salts thereof; Maleic acid, fumaric acid, esters and anhydrides thereof; Styrene, acrylonitrile, vinylidene chloride, vinyl ether and the like. Among these, the dispersion stabilizer for suspension polymerization of the present invention is particularly preferably used for suspension polymerization of vinyl chloride alone or with a monomer capable of copolymerizing vinyl chloride and vinyl chloride. As a monomer which can copolymerize with vinyl chloride, Vinyl ester, such as vinyl acetate and a vinyl propionate; (Meth) acrylic acid esters, such as methyl (meth) acrylate and ethyl (meth) acrylate; Α-olefins such as ethylene and propylene; Unsaturated dicarboxylic acids such as maleic anhydride and itaconic acid; Acrylonitrile, styrene, vinylidene chloride, vinyl ether, etc. are mentioned.

An oil-soluble or water-soluble polymerization initiator that has conventionally been used for polymerization of vinyl chloride can be used for suspension polymerization of a vinyl compound. As an oil-soluble polymerization initiator, For example, Percarbonate compounds, such as diisopropyl peroxy dicarbonate, di-2-ethylhexyl peroxy dicarbonate, diethoxy ethyl peroxy dicarbonate; perester compounds, such as t-butyl peroxy neodecanoate, t-butyl peroxy pivalate, t-hexyl peroxy pivalate, and (alpha)-cumyl peroxy neodecanoate; Peroxides such as acetylcyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, 3,5,5-trimethylhexanoyl peroxide and lauroyl peroxide; Azo compounds, such as azobis-2, 4- dimethylvaleronitrile and azobis (4-2, 4- dimethylvaleronitrile), etc. are mentioned. As a water-soluble polymerization initiator, potassium persulfate, ammonium persulfate, hydrogen peroxide, cumene hydroperoxide, etc. are mentioned, for example. These oil-soluble or water-soluble polymerization initiators can be used individually or in combination of 2 or more types.

In suspension polymerization of a vinyl compound, there is no restriction | limiting in particular in superposition | polymerization temperature, Of course, it can also adjust to the high temperature exceeding 90 degreeC as well as the low temperature of about 20 degreeC. Moreover, in order to raise the heat removal efficiency of a polymerization reaction system, you may use the polymerization machine with a reflux condenser.

In the suspension polymerization of the vinyl compound, in addition to the composition (C) and PVA (E), methylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and the like, which are usually used when the vinyl compound is suspended in an aqueous medium, etc. Water-soluble cellulose ethers; Water-soluble polymers such as gelatin; Oil-soluble emulsifiers such as sorbitan monolaurate, sorbitan triorate, glycerin tristearate, and ethylene oxide propylene oxide block copolymers; You may use together water-soluble emulsifiers, such as polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerol oleate, and sodium laurate. Although there is no restriction | limiting in particular about the addition amount, 0.01 mass part or more and 1.0 mass part or less are preferable per 100 mass parts of vinyl compounds.

The vinyl polymer obtained by the manufacturing method of this invention mix | blends a plasticizer etc. suitably, and can be used for various molded article uses.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. In the following examples and comparative examples, "part" and "%" represent a mass part and mass%, respectively, unless there is particular notice.

[Viscosity Average Polymerization Degree of PVA]

The viscosity average polymerization degree of PVA was measured according to JIS-K6726 (1994). Specifically, when the degree of saponification is less than 99.5 mol%, the intrinsic viscosity [η] (liter / g) measured at 30 ° C in water with respect to the saponified PVA until the saponification degree is 99.5 mol% or more is used. The viscosity average polymerization degree (P) was calculated | required by the following formula.

P = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

[PVA saponification degree]

The saponification degree of PVA was calculated | required by the method as described in JIS-K6726 (1994). In addition, the saponification degree of modified PVA (A) is the value measured about the modified PVA (A) by reprecipitating and refine | purifying the powder which consists of obtained composition (C).

[Amount of Double Bond Introduced in Modified PVA (A)]

A 10% aqueous solution of the composition (C) was prepared. 5 g of this aqueous solution was dripped in 500 g of a solution of methyl acetate / water = 95/5 to precipitate the modified PVA (A), and was recovered and dried. For the isolated modified PVA (A), the amount of double bond introduced into the modified PVA (A) was measured using ¹ H-NMR. In addition, the quantity of the said double bond is the quantity of the double bond with respect to the whole monomeric unit of modified PVA (A).

[Water Insolubles in Aqueous Solution of Composition (C)]

The presence or absence of an insoluble matter was visually observed with respect to the 10% aqueous solution of the composition (C) prepared in the measurement of the amount of the double bond introduced into the modified PVA (A).

[Yellow Degree of Powder Consisting of Composition (C)]

The yellowness (YI) of the powder composed of the composition (C) is less than 100 µm and more than 1000 µm using a sieve (mesh size: 100 µm, 1000 µm) with respect to the powder composed of the composition (C). After removing, measurement was performed using a color meter (SM-T-H1 manufactured by Suga Shikenki). In addition, yellowness is the value measured and calculated according to JIS-Z8722 (2009) and JIS-K7373 (2006).

Production Example 1 (Production of Composition 1)

A solution obtained by dissolving 0.88 parts of maleic anhydride as an unsaturated carboxylic acid and 0.1 parts of propyl gallate as 150 parts of methanol as a compound (B) was prepared, and there were 100 parts of PVA-1 (viscosity average polymerization degree 800, saponification degree 72 mol%) as a raw material PVA. In addition, after swelling, methanol was removed under reduced pressure. Then, the obtained mixed powder is heat-treated at 105 degreeC for 4 hours, and contains modified PVA (A) and compound (B) which have a double bond derived from maleic anhydride in a side chain as a composition (C). The powdery composition 1 was obtained. The said modified PVA (A) confirmed the peak of the double bond introduced in the vicinity of 6.0-6.5 ppm, and the quantity of the double bond was 0.12 mol%. In addition, the viscosity average polymerization degree of the said modified PVA (A) was 800, and saponification degree was 72 mol%. Yellowness (YI) of the powder of Composition 1 was 20.2. In addition, the particle diameter of the composition 1 calculated | required by JIS-K6726 (1994) was 530 micrometers. In addition, when the 10% aqueous solution of Composition 1 was prepared, no insoluble matter was found in the aqueous solution.

Preparation Examples 2 to 19 (Preparation of Compositions 2 to 19)

Compositions 2 to 17 were produced in the same manner as in the preparation of composition 1, except that the kind and amount of the raw material PVA, unsaturated carboxylic acid or derivatives thereof used, the kind and amount of the compound (B), the heat treatment temperature, and the heat treatment time were changed. . Production conditions and production results are shown in Table 1.

Example 1

100 parts of the composition 1 was dissolved in deionized water as a dispersion stabilizer for suspension polymerization, and injected into the autoclave. The density | concentration of the composition 1 in aqueous solution is 600 ppm with respect to the injection amount of vinyl chloride. Subsequently, as PVA (E), 100 parts of PVA of 2400 degree of viscosity average degree of polymerization and 88 mol% of saponification degree were dissolved in deionized water, and injected into the autoclave. The concentration of PVA (E) in the aqueous solution is 360 ppm relative to the injection amount of vinyl chloride. Subsequently, deionized water was added and injected so that the sum total of deionized water might be 1200 parts.

Next, 0.65 parts of a 70% toluene solution of cumylperoxy neodecanoate and 1.05 parts of a 70% toluene solution of t-butylperoxy neodecanoate were injected into the autoclave, and nitrogen was introduced into the autoclave so that the pressure was 0.2 MPa. . Subsequently, the operation of purging nitrogen was performed five times in total. After nitrogen was completely removed by completely replacing the inside of the autoclave, 940 parts of vinyl chloride were injected. The contents in the autoclave were raised to 57 ° C. to initiate the polymerization of vinyl chloride under stirring. At the start of the polymerization, the pressure in the autoclave was 0.80 MPa. About 3.5 hours after the start of the polymerization, the polymerization was stopped when the pressure in the autoclave reached 0.70 MPa, and after the unreacted vinyl chloride was removed, the polymerization reaction product was taken out and dried at 65 ° C. for 16 hours. Vinyl resin (vinyl chloride polymer particle) was obtained. And the particle | grains obtained by the method shown below were evaluated. The evaluation results are shown in Table 2.

(Evaluation of Vinyl Chloride Polymer Particles)

About the obtained vinyl chloride polymer particle, (1) average particle diameter, (2) particle size distribution, (3) fish eye, and (4) color (yellowness: YI) were evaluated in accordance with the following method. The evaluation results are shown in Table 2.

(1) average particle diameter

The particle size distribution was measured by the dry sieve separation method described in JIS-Z8815 (1994) using the wire mesh of the Tyler mesh standard. From the result, the average particle diameter was calculated using the Rosin-Rammler plot.

(2) particle size distribution

The content of JIS standard sieve 42 mesh-on was expressed in mass%. The evaluation results are shown in Table 2.

 A: less than 0.5%

 B: 0.5% or more but less than 1%

 C: 1% or more

The content of the JIS standard sieve 60 mesh-on was expressed in mass%. The evaluation results are shown in Table 2.

 A: less than 5%

 B: 5% or more but less than 10%

 C: more than 10%

In addition, the content of 42 mesh-on and content of 60-mesh on both, the smaller the value, the less coarse and large particles, the sharper the particle size distribution, which means that the polymerization stability is excellent.

(3) fish eye

100 parts of the obtained vinyl chloride polymer particles, 50 parts of DOP (dioctylphthalate), 5 parts of tribasic lead sulfate and 1 part of zinc stearate were roll kneaded at 150 ° C. for 7 minutes to prepare a sheet having a thickness of 0.1 mm, and a fish eye per 1000 cm 2. The number of was measured.

(4) color (YI)

100 parts of the obtained vinyl chloride polymer particles, 3 parts of TVS # N-2000E (manufactured by Nitto Kasei), which is a tin stabilizer, and 0.01 part of ultramarine blue were roll-kneaded at a thickness of 0.4 mm for 10 minutes at 170 ° C, and then the obtained sheet was 185 ° C. And pressing while heating at a pressure of 120 kg / cm 2 for 5 minutes, and then pressing while cooling at 20 ° C. and a pressure of 150 kg / cm 2 for 5 minutes to produce a thick film of 42 × 25 × 5 mm.

The color (YI) of the produced thick film was measured according to JIS-K7105 (1981) using a color meter (SM-T-H1 manufactured by Suga Shikenki). As the value increased, the vinyl chloride polymer was decomposed by heat and colored yellow.

Examples 2-9

Suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1 except that the kind and amount of the composition (C) used as the dispersion stabilizer for suspension polymerization and the kind and amount of the PVA (E) were changed. The conditions and the results are shown in Table 2.

Comparative Example 1

The suspension polymerization of vinyl chloride was performed like Example 1 except having changed the usage-amount of the composition 1 and PVA (E) as shown in Table 2. The results are shown in Table 2. Since the amount of the composition (C) was too small, polymerization was unstable, and the resultant vinyl chloride polymer particles had a large average particle diameter, a large proportion of coarse and large particles, and many fish eyes.

Comparative Example 2

Suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that Composition 10 was used as the composition (C) and PVA (E) was not used. The results are shown in Table 2. Since PVA (E) was not used, polymerization was unstable, and the resultant vinyl chloride polymer particles had a large average particle diameter, a large proportion of coarse and large particles, and many fish eyes.

Comparative Example 3

Suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 11 was used as the composition (C). The results are shown in Table 2. Since the polymerization degree and saponification degree of the modified PVA (A) contained in the composition 11 are too high, and the polymerization degree and saponification degree of the PVA (E) are too low, the average particle diameter of the obtained vinyl chloride polymer particles is large, There were many ratios, and fish eye resulted in many.

Comparative Example 4

Suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 12 was used as the composition (C). The results are shown in Table 2. Since no double bonds derived from unsaturated carboxylic acids or unsaturated carboxylic acid derivatives were introduced into the composition 12, polymerization was unstable, resulting in a large average particle diameter of the obtained vinyl chloride polymer particles, a large proportion of coarse and large particles, and a large number of fish eyes. Became.

Comparative Example 5

The suspension polymerization of vinyl chloride was performed like Example 1 except having used the composition 13 as composition (C). The results are shown in Table 2. Since the composition 13 did not contain the compound (B), the color of the composition 13 itself was bad, the color of the vinyl chloride polymer obtained was poor even when used for suspension polymerization, resulting in many fish eyes. In addition, when the 10% aqueous solution of the composition 13 was prepared, an insoluble matter appeared in the aqueous solution.

Comparative Example 6

Suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 14 was used as the composition (C). The results are shown in Table 2. Since the composition 14 did not contain the compound (B), the color of the composition 14 itself was bad, the color of the obtained vinyl chloride polymer was bad even when used for suspension polymerization, resulting in many fish eyes.

Comparative Example 7

Suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 15 was used as the composition (C). The results are shown in Table 2. Since the composition 15 uses sorbic acid (a compound having no two or more hydroxyl groups bonded to a conjugated double bond) as the compound (B), the color of the composition 15 itself is poor and vinyl chloride obtained even when used for suspension polymerization. The color of the polymer was bad, resulting in many fish eyes. In addition, when the 10% aqueous solution of the composition 15 was prepared, an insoluble matter appeared in the aqueous solution.

Comparative Example 8

Suspension polymerization of vinyl chloride was performed like Example 1 except having used composition 16 as composition (C). The results are shown in Table 2. In the modified PVA (A) contained in the composition 16, since the bond amount of the double bond derived from an unsaturated carboxylic acid or its derivative is small, superposition | polymerization is unstable and the average particle diameter of the vinyl chloride polymer particle obtained is large, There were many ratios, and fish eye resulted in many.

Comparative Example 9

Suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 17 was used as the composition (C). The results are shown in Table 2. In the modified PVA (A) contained in the composition 17, since the bond amount of the double bond derived from an unsaturated carboxylic acid or its derivative is large, the color of the composition 17 itself is poor, and the color of the vinyl chloride polymer obtained even when used for suspension polymerization is It's bad, and the fish eye has a lot of results. In addition, when the 10% aqueous solution of the composition 17 was prepared, an insoluble matter appeared in the aqueous solution.

Comparative Example 10

Suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 18 was used as the composition (C). The results are shown in Table 2. Since the composition 18 did not contain the compound (B), the color of the composition 18 itself was bad, the color of the vinyl chloride polymer obtained was poor even when used for suspension polymerization, resulting in many fish eyes. Moreover, when preparing the 10% aqueous solution of the composition 18, insoluble matter appeared in the aqueous solution.

Comparative Example 11

Suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 19 was used as the composition (C). The results are shown in Table 2. Since the composition 19 contained many compound (B), superposition | polymerization was unstable, the average particle diameter of the vinyl chloride polymer particle obtained was large, there were many ratios of a coarse and large particle | grain, and many fish eye resulted.

As shown in the examples, in the preparation of the vinyl chloride copolymer, by using a specific composition and a specific PVA in combination as a dispersion stabilizer for suspension polymerization, the polymerization stability, color is excellent, and coarse and large particles are produced It is possible to provide a vinyl chloride polymer with little. Therefore, the industrial utility of the present invention is very high.

Claims (3)

As a manufacturing method of the vinyl polymer which suspend-polymerizes a vinyl compound in presence of the dispersion stabilizer for suspension polymerization;
The said dispersion stabilizer contains the composition (C) and polyvinyl alcohol (E) containing a modified polyvinyl alcohol (A) and a compound (B),
The modified polyvinyl alcohol (A) has a double bond derived from an unsaturated carboxylic acid or a derivative thereof in a side chain of 0.01 mol% or more and less than 2 mol%,
The saponification degree of the modified polyvinyl alcohol (A) is 65 mol% or more and less than 77 mol%, the viscosity average polymerization degree is 400 or more and less than 1500,
Compound (B) is a compound having two or more hydroxyl groups bonded to a conjugated double bond, a salt thereof, or an oxide thereof,
Saponification degree of polyvinyl alcohol (E) is 77 mol% or more and less than 97 mol%, viscosity average degree of polymerization is 1500 or more and less than 5000,
Content of the compound (B) in a composition (C) is 0.001 mass part or more and less than 5 mass parts with respect to 100 mass parts of modified polyvinyl alcohol (A),
The mass ratio (C / E) of a composition (C) and a polyvinyl alcohol (E) is 50/50-90/10, The manufacturing method characterized by the above-mentioned. The production method according to claim 1, wherein the compound (B) is a compound having two or more hydroxyl groups bonded to carbon constituting the aromatic ring, or a salt thereof or an oxide thereof. The process according to claim 1 or 2, wherein the composition (C) is a powder and the yellow index of the powder is less than 50.